As a sliding-type automobile seat of this kind, a sliding-type automobile seat is disclosed in Japanese Patent Application Laid-Open No. 2004-51082. Referring now to FIGS. 1 to 5, the conventional sliding-type automobile seat will be discussed in order to facilitate understanding of the present invention. As shown in FIG. 1, this automobile seat includes a seat cushion frame 1 for a seat cushion thereof. The seat cushion frame 1 comprises a pair of spaced apart side frame sections 1a, a pan frame section 1b arranged and fixed between forward portions of the side frame sections 1a, and a rear frame section 1c arranged and fixed between rearward portions of the side frame sections 1a. 
The automobile seat can be slidingly moved forward and rearward in an automobile via a slide rail mechanism 2. As shown in FIG. 2, the slide rail mechanism 2 comprises upper rails 2a attached to lower portions of the side frame sections 1a (only one side frame section 1a and only one upper rail 2a are shown in FIG. 2), and a pair of parallel lower rails 2b mounted on a floor surface of the automobile via stand leg portions 3a, 3b (only one lower rail 2b is shown in FIG. 2). The upper rails 2a are slidably engaged with the lower rails 2b as will be fully discussed hereinafter, whereby the seat can be slidingly moved forward and rearward in the automobile.
As shown in FIG. 3, each of the upper rails 2a (only one upper rail 2a is shown in FIG. 3) comprises a pair of members 20a, 20b of substantially J-shapes in vertical-section that are fixed back-to-back to a lower portion of a corresponding side frame section 1a of the automobile seat by a support pin 40 and hang downward from the side frame section 1a. Each of the lower rails 2b (only one lower rail 2b is shown in FIG. 3) has a longitudinal body 21 of a substantially U-shape in cross-section and is mounted on the floor surface of the automobile with an opening portion thereof facing upward. The lower rail body 21 includes inward bent flanges 22a, 22b of substantially L-shapes in cross-section that are bent inward from both ends of the substantially U-shaped lower rail body 21 in such a manner to allow a space to be produced between the inward bent flanges 22a, 22b. 
Each of the upper rail 2a is combined with a corresponding lower rail 2b by causing lower curved portions 20a′, 20b′ of the substantially J-shaped members 20a, 20b hanging downward from the side frame section la to be inserted into the substantially U-shaped lower rail body 21 through the space between the inward bent flanges 22a, 22b of the lower rail body 21, and causing tip end portions of the lower curved portions 20a′, 20b′ to be arranged inside the inward bent flanges 22a, 22b of the lower rail body 21. Moreover, between the lower curved portions 20a′, 20b′ of the substantially J-shaped members 20a, 20b of the upper rail body 21 and a bottom surface of the lower rail body 21, a plurality of rollers 23 are disposed (only one roller 23 is shown in FIG. 3), whereby the seat can be smoothly slid along the lower rails.
The sliding-type automobile seat is provided with slide lock mechanisms for causing the seat to be locked at predetermined positions with respect to the lower rails 2b. As shown in FIG. 4, the slide lock mechanisms include lock plates 4 arranged at side portions of the upper rails 2a (only one upper rail 2a and only one lock plate 4 are shown in FIG. 4). An operating lever 5 for releasing the seat from a locked condition is provided so as to be bridged between the lock plates 4.
Again referring to FIGS. 3 and 4, each of the lock plates 4 extends along the side portions of the substantially J-shaped members 20a, 20b of a corresponding upper rail 2a. The lock plate 4 is pivotally supported, at the substantially middle portion of its longitudinal direction, to the side portions of the substantially J-shaped members 20a, 20b of the upper rail 2a by the support pin 40, whereby the lock plate 4 is vertically swingable around the support pin 40. Moreover, the lock plate 4 is formed, at its region adjacent a rear end portion thereof, with an elongated hole 41 vertically extending. A guide pin 42 projects from the side portion of the upper rail 2a and is inserted through the elongated hole 41 formed in the lock plate 4, so that the vertical swinging movement of the lock plate 4 is guided along the elongated hole 41.
The lock plate 4 is urged by a coil spring 43 so as to be always pulled upward at the rear end portion thereof. More particularly, the coil spring 43 is retained at one end portion thereof to a protruding piece 43a provided at a corresponding side frame section 1a, and retained at the other end portion thereof to a protruding piece 43b bent from an upper edge of the lock plate 4, whereby the coil spring 43 is provided between the side frame section 1a and the lock plate 4.
Each of the slide lock mechanisms further includes first and second engaging means. The first engaging means comprises an engaging piece 44 projecting laterally from a lower edge of a corresponding lock plate 4 and a plurality of receiving holes 45 formed in the engaging piece 44. The lower curved portions 20a′, 20b′ of the substantially J-shaped members 20a, 20b of the upper rail 2a are formed with slits 46. The engaging piece 44 of the lock plate 4 projects so as to cross the inward bent flange 22a of the lower rail 2b through the slits 46.
The second engaging means includes a plurality of protruding teeth 47 that are formed by making a lower portion of an inward bent flange 22a of a corresponding lower rail 2b into a concave/convex form. The protruding teeth 47 are releasably engaged with the receiving holes 45 formed in the engaging piece 44 of the lock plate 4.
The operating lever 5 is formed in a substantially U-shape as viewed from above by causing a pipe material to be bent. Both end portions of the U-shaped operating lever 5 are flatly crushed and welded to forward portions of the lock plates 4, whereby the operating lever 5 is connected to the lock plates 4. As shown in FIG. 1, the operating lever 5 is bridged between the lock plates 4 and arranged under the seat cushion frame 1 with a forward portion thereof projecting forward of the seat.
In the slide lock mechanisms, the lock plates 4 are always urged upward at the rear end portions thereof by the coil springs 43 and the engaging pieces 44 are releasably meshed at the receiving holes 45 thereof with the protruding teeth 47 as shown in FIG. 4, whereby the upper rails 2a are locked with respect to the lower rails 2b so as to be unable to be slid relative to the lower rails 2b. On the other hand, when the operating lever 5 is pulled up in such a direction that it approaches the seat cushion frame, namely, in such a direction as to be indicated in FIG. 5 by an arrow, the rear end portions of the lock plates 4 are swung downward about the support pins 40 against the actions of the coil springs 43, whereby the receiving holes 45 of the lock plates 4 are released from the engagement with the protruding teeth 47 of the lower rails 2b, the engagement of the upper rails 2a with respect to the lower rails 2b is therefore released, and the seat is brought to a condition where it can be slidingly moved forward and rearward in the automobile.
In a case where the conventional automobile seat constructed as discussed above is assembled, it is necessary to cause the lock plates to be individually mounted to the upper rails. However, since the lock plates are previously welded to the both end portions of the substantially U-shaped operating lever, when such lock plates are individually mounted to the upper rails, mounting work of one of the lock plates to one of the upper rails will be interrupted by the other of the lock plates as well as the operating lever and a lot of time is taken for connecting of the operating lever to the lock plates and assembling the entire lock mechanisms.
Moreover, in the automobile provided with the seat constructed as discussed above, when any baggage, luggage, etc. is put on the floor surface of the automobile while being carelessly contacted with the operating lever, there is a possibility that the operating lever and/or the baggage, luggage, etc. will be damaged or deformed and the operating lever can not be properly operated. In this condition, if the operating lever is forcedly operated, there is a possibility that the operating lever will cause the baggage, luggage, etc. to be damaged or deformed.
The present invention has been made in view of the above-mentioned problems of the prior art automobile seat.
It is therefore an object of the present invention to provide a sliding-type automobile seat which facilitates connecting of an operating lever to slide lock mechanisms of the sliding-type automobile seat.
It is another object of the present invention to provide a sliding-type automobile seat which is simply constructed and in which even if any baggage, luggage, etc. is contacted with the operating lever of the automobile seat, the baggage, luggage, etc. and/or the operating lever of the automobile seat can be prevented from being damaged or deformed.